Randy Stewart, 18, is transferred from the Harris County Sheriff Office Building to a patrol vehicle, Monday, Nov. 11, 2013, in Houston. When asked if he knew the victim he answered "he was my brother".
Photo: Marie D. De Jesus, Houston Chronicle

Randy Stewart, 18, is transferred from the Harris County Sheriff...

Randy Stewart, 18, is transferred from the Harris County Sheriff Office Building to a patrol vehicle, Monday, Nov. 11, 2013, in Houston. When asked if he knew the victim he answered "he was my brother".
Photo: Marie D. De Jesus, Houston Chronicle

Randy Stewart, 18, is transferred from the Harris County Sheriff...

Randy Stewart, 18, is transferred from the Harris County Sheriff Office Building to a patrol vehicle, Monday, Nov. 11, 2013, in Houston. When asked if he knew the victim he answered "he was my brother".
Photo: Marie D. De Jesus, Houston Chronicle

Randy Stewart, 18, is transferred from the Harris County Sheriff...

Brayiannia Young speaks with the media during a press conference outside Ben Taub hospital on Monday, Nov. 11, 2013, in Houston. Brayiannia was shot during a house party where two people were killed and 19 injured in the Cypress area on Saturday night. Her brother, Willie Young, 21, was arrested and charged with deadly conduct on Monday. A second suspect Randy Stewart, 18, was arrested and charged with aggravated assault. She claims her brother could not have done the shooting.
Photo: J. Patric Schneider, For The Chronicle

Brayiannia Young speaks with the media during a press conference...

Quanell X walks with Brayiannia Young after a press conference outside Ben Taub hospital on Monday, Nov. 11, 2013, in Houston. Brayiannia was shot during a house party where two people were killed and 19 injured in the Cypress area on Saturday night. Her brother, Willie Young, 21, was arrested and charged with deadly conduct on Monday. A second suspect Randy Stewart, 18, was arrested and charged with aggravated assault. She claims her brother could not have done the shooting.
Photo: J. Patric Schneider, For The Chronicle

Quanell X walks with Brayiannia Young after a press conference...

Quanell X stands with Brayiannia Young during a press conference outside Ben Taub hospital on Monday, Nov. 11, 2013, in Houston. Brayiannia was shot during a house party where two people were killed and 19 injured in the Cypress area on Saturday night. Her brother, Willie Young, 21, was arrested and charged with deadly conduct on Monday. A second suspect Randy Stewart, 18, was arrested and charged with aggravated assault. She claims her brother could not have done the shooting.
Photo: J. Patric Schneider, For The Chronicle

Quanell X stands with Brayiannia Young during a press conference...

Quanell X stands with Brayiannia Young, left, and her mother Yolanda during a press conference outside Ben Taub hospital on Monday, Nov. 11, 2013, in Houston. Brayiannia was shot during a house party where two people were killed and 19 injured in the Cypress area on Saturday night. Her brother, Willie Young, 21, was arrested and charged with deadly conduct on Monday. A second suspect Randy Stewart, 18, was arrested and charged with aggravated assault. She claims her brother could not have done the shooting.
Photo: J. Patric Schneider, For The Chronicle

Quanell X stands with Brayiannia Young, left, and her mother...

Debris remains scattered on the lawn of the Cypress home where two teens were killed and more than one dozen were injured when shots broke out at a party Saturday night.

Photo: Johnny Hanson, Houston Chronicle

Debris remains scattered on the lawn of the Cypress home where two...

Pictured is the house where two Katy ISD students were killed Saturday, Nov. 9, 2013, during a party.

Photo: Johnny Hanson, Houston Chronicle

Pictured is the house where two Katy ISD students were killed...

Tonya Grice uses hydrogen peroxide to clean the blood from the walkway of her sister's Cypress-area house, where two teenagers were killed and about 20 more wounded late Saturday when gunfire erupted at an 18-year-old's birthday party.
Photo: Eric Kayne

Tonya Grice uses hydrogen peroxide to clean the blood from the...

Students attend school at Morton Ranch High School Monday.

Photo: Johnny Hanson, Houston Chronicle

Students attend school at Morton Ranch High School Monday.

Students attend school at Morton Ranch High School Monday morning. Two Morton Ranch students were killed in a shooting that broke out at a house party Saturday night.

Photo: Johnny Hanson, Houston Chronicle

Students attend school at Morton Ranch High School Monday morning....

Partygoers B.T. Tucker, left, Mariah Boulden, 18, center, and Lank, who wished to only be referred by his first name, talk to the media Sunday, Nov. 10, 2013 outside Mariah's home where two people were killed and at least 20 others injured late Saturday when gunfire erupted during her birthday party in the Cypress area in Houston. Harris County Sheriff Adrian Garcia said the gathering Saturday night that drew more than 100 people, most of them 17- to 19-year-olds, became a “birthday party gone wild.” (AP Photo/Houston Chronicle, J. Patric Schneider)

Harris County Sheriff Adrian Garcia talks to the media Sunday, Nov. 10, 2013 outside a home where two people were killed and at least 20 othersinjured late Saturday when gunfire erupted during a house party in the Cypress area. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, in Houston. (AP Photo/Houston Chronicle, J. Patric Schneider)
Photo: J. Patric Schneider, Associated Press

Partygoers ran down the street after gunfire erupted on Enchanted Springs, ducking behind vehicles and leaving bloody palm prints like this one on a car hood across from the house party.
Photo: Eric Kayne

Partygoers ran down the street after gunfire erupted on Enchanted...

Blood stains the carpet and wall inside the home where shooting erupted, resulting in the deaths of two people and injuries to 20 others Saturday when gunfire erupted at a house party in the Cypress area.
Photo: Eric Kayne

Blood stains the carpet and wall inside the home where shooting...

Blood stains the carpet and wall inside the home where shooting erupted, resulting in the deaths of two people and injuries to 20 others Saturday when gunfire erupted at a house party in the Cypress area.
Photo: J. Patric Schneider, Freelance

Blood stains the carpet and wall inside the home where shooting...

A parent waits for news after the shooting late Saturday night at a birthday party in the Cypress area.

Photo: Anita Hassan, Houston Chronicle

A parent waits for news after the shooting late Saturday night at a...

Parent waits on a child at the scene of a Cypress-area shooting.

Photo: Anita Hassan, Houston Chronicle

Parent waits on a child at the scene of a Cypress-area shooting.

Firemen wash away a pool of blood down the street from where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.

Photo: Eric Kayne, For The Chronicle

Firemen wash away a pool of blood down the street from where two...

Tonya Grice uses hydrogen peroxide to clean the blood from the walkway of her sister's house where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: Eric Kayne, For The Chronicle

Tonya Grice uses hydrogen peroxide to clean the blood from the...

Tonya Grice uses hydrogen peroxide to clean the blood from the driveway of her sister's house where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: Eric Kayne, For The Chronicle

Tonya Grice uses hydrogen peroxide to clean the blood from the...

Blood is splattered near the front entrance of a home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: Eric Kayne, For The Chronicle

Blood is splattered near the front entrance of a home where two...

Blood stains lie on the side of a home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: Eric Kayne, For The Chronicle

Blood stains lie on the side of a home where two people were killed...

Blood stains lie on the carpet and wall inside a home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: Eric Kayne, For The Chronicle

Blood stains lie on the carpet and wall inside a home where two...

Blood splatter lies in the driveway of a home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: Eric Kayne, For The Chronicle

Blood splatter lies in the driveway of a home where two people were...

Blood is pooled down the street from where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: Eric Kayne, For The Chronicle

Blood is pooled down the street from where two people were killed...

Blood splatter could be found across driveways and in the street near where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: Eric Kayne, For The Chronicle

Blood splatter could be found across driveways and in the street...

A person is interviewed in front of the home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: Eric Kayne, For The Chronicle

A person is interviewed in front of the home where two people were...

An unidentified woman walks away from the home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.

Photo: Eric Kayne, For The Chronicle

An unidentified woman walks away from the home where two people...

Shaniqua Brown, 17, left, who was at the party, and her mother Mary Brown stand in front of a home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted at a house party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.

Photo: Eric Kayne, For The Chronicle

Shaniqua Brown, 17, left, who was at the party, and her mother Mary...

Mariah Boulden,18, stands outside her home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted during her birthday party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: J. Patric Schneider, For The Chronicle

Mariah Boulden,18, stands outside her home where two people were...

Mariah Boulden,18, stands outside her home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted during her birthday party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.
Photo: J. Patric Schneider, For The Chronicle

Mariah Boulden,18, stands outside her home where two people were...

Mariah Boulden,18, stands outside her home where two people were killed and at least 16 others wounded late Saturday when gunfire erupted during her birthday party in the Cypress area, authorities said. The shooting broke out about 11:15 p.m. in the 7300 block of Enchanted Creek Drive, near Fry and FM 529. Nov. 10, 2013 in Houston.

Photo: J. Patric Schneider, For The Chronicle

Mariah Boulden,18, stands outside her home where two people were...

Students attend school at Morton Ranch High School Monday morning. Two Morton Ranch students were killed in a shooting that broke out at a house party Saturday night.

Prosecutors Tuesday said they believe at least two other gunmen connected to a fatal weekend house party are still on the loose.

One of the shooters being sought is likely responsible for the slayings of two Katy ISD students who were at the party, Assistant Harris County District Attorney Katherine McDaniel told reporters outside a Harris County courtroom.

"We believe there are additional shooters, multiple guns that haven't been recovered and multiple gangs involved," said McDaniel.

Two men, 18-year-old Randy Stewart and 21-year-old Willie Young, were on a court docket Tuesday morning, but did not appear. Their cases were rescheduled without action.

McDaniel painted a picture of a Saturday night explosion of gunfire in the midst of a 100 person house party in a residential area of Cypress with two teens being killed.

Qu'eric Danarius Bernard Richardson, 17, and Arielle Shepherd, both students at Morton Ranch High School in the Katy Independent School District, were killed as the violence spilled out of the house.

"It was a melee and people were running for their lives," McDaniel said.

Richardson was shot in the head while running away from the house party in the 7300 block of Enchanted Creek. Shepherd, a sophomore, was shot in the torso inside the house. She died at a Houston-area hospital.

Because Stewart and Richardson appeared to have known each other and were connected to a pending check forgery charge, McDaniel said it is "likely" that the person who shot the teen is still on the loose.

"I think it's a fair assumption that the shooting occurred as part of a gang dispute," McDaniel said. "At this point, we believe there are at least two other shooters."

McDaniel said investigators believe Richardson may have known one of the accused gunmen.

Stewart is named in an October forgery case, accused of making out a stolen check in the amount of $460 to Richardson, according to the criminal complaint.

Following his arrest Monday, Stewart responded to reporters' questions about Richardson by saying, "he was my brother."

Nineteen others were injured when gunfire erupted at the party just before 11 p.m. Saturday. In all, 16 people were treated for gunshot wounds. The others suffered injuries related to falls or the crush of people trying to get out of the house.

Investigators estimated that more than 100 people packed the suburban home for the 18th birthday party of a classmate after it was promoted through Twitter, Instagram, Facebook and text messages. The Harris County Sheriff's Office said the violence is believed to have begun after someone fired a gun into the ceiling during the party, and someone else began shooting into the crowd.

Stewart and Young are being held in the Harris County Jail in lieu of $250,000 bail each.

Neither has been charged in the deaths of Richardson and Shepherd.

Innocence claimed

Their charges stem from eyewitness statements identifying them as firing guns at the party. Young is accused of shooting a party-goer in the arm, while Stewart is charged with firing shots into the crowd. The charges could be upgraded as investigators gather more evidence.

People at Stewart's home refused to speak to reporters Monday, while Young's mother and sister called a news conference to say police have the wrong man.

Yolanda Young said she sent her son to retrieve her daughter when she learned the 17-year-old was at a raucous house party.

"All I know is, my son is innocent. I want an apology from the police for what they put my family through," she said outside Ben Taub General Hospital Monday night where her daughter was treated for a gunshot wound and released.

The teen said she did not know who shot her in the foot. "Everybody was trying to get under the table and I was getting under the table," Brayiannia Young said.

She said Willie Young helped shuttle shooting victims, including her, to the hospital.

Tears at school

The mood was grim Monday as students returned to the Morton Ranch High School campus, where officials broadcast an announcement about the shooting.

"There were a lot of people crying," said Carlos Garcia, 16. "It was pretty depressing."

Several students said it is common to rely on social media to make mass announcements about parties.

"They send it (the Twitter message) out and whoever sees it, goes to the party," Garcia said. "But, that's what they were risking: that other people show up who don't like them."

Marcus Ott, 18, a recent graduate of Cypress-Fairbanks ISD, said he was trying to leave the party when shots rang out. He said two of his brothers were wounded, one in the chest and the other in the elbow. "Everybody was having a good time before I left, and I don't know what happened," Ott said.

Ott and others said there were people at the party affiliated with gangs. No one Monday would say if Stewart or Young were affiliated with a gang. Both have arrest records.

Stewart pleaded guilty earlier this year to a terroristic threat, a misdemeanor in which he and four other men assaulted a Cypress Woods High School student, then threatened to kill him. Months later, Stewart was accused of going to the home of a classmate with three of those men and taking a video game console and a tablet computer. That case was dismissed after the victim stopped cooperating with authorities.

The forgery case against Stewart remains pending.

Young was arrested earlier this year on a charge of evading arrest, but that case was dismissed.

Richardson also had been arrested for evading arrest this year. His case was pending.

Security heightened

Meanwhile, school officials bolstered security at campuses.

"Our sympathies go out to the families of these students whose lives were cut short by this tragedy," said Superintendent Alton Frailey in a statement. "In light of this fact, Katy ISD police will continue to have a greater presence on campus this week so students can feel more secure."

Cypress-Fairbanks ISD released a statement on Monday saying that Young and Stewart were former Cypress Springs High School students.

One of the suspects "withdrew from the district in January 2013 and the other in February 2009," according to the statement.

Officials also postponed a basketball game between the two schools scheduled for Tuesday.